The present invention relates to a heating, ventilation and/or air-conditioning device including a thermal loop equipped with a heat exchanger.
Heat exchangers, particularly evaporators are known which consist of a stack of plates having opposite first and second longitudinal ends some of which have separation elements intended to divert a flow of cooling liquid circulating in an axial direction of the evaporator so as to direct it to a channel region in which it travels from one said end to the other in a longitudinal direction of the plates.
The partition plates and, more generally, the chamber passages in evaporators with brazed plates are designed to meet the requirements of mechanical strength and to promote a balanced distribution of the cooling fluid in the various channels. Likewise, the parts of the coolant ducts close to the inlet and outlet manifolds meet the same requirements, while also seeking to promote turbulence of the flow in order to intensify the heat exchanges.
In its current design, which makes it possible to reconcile mechanical strength and high level of heat exchange, the geometry is a source of turbulence and of breakaway flow of the cooling fluid which are likely to generate noise emission causing discomfort for the user.
The present invention proposes to reduce the flow noise which is generated on the outside by the evaporator.
To this end the invention proposes to limit the vibratory excitation of the partition plates or even of the end plates.
One basic idea of the invention, according to a first aspect, is to limit the excitation in the regions where the cooling fluid arrives on the walls of the exchanger with a speed component perpendicular to the wall, this being obtained by adding stiffening elements which make it possible to limit the response of the wall to the frontal impacts of the fluid.
According to its first aspect, the invention thus relates to a heating, ventilation and/or air-conditioning device including a thermal loop equipped with a heat exchanger, for example an evaporator, said heat exchanger consisting of a stack of orientation plates having first and second ends called opposite longitudinal ends, and having end plates arranged at two opposite axial ends of the heat exchanger, certain orientation plates having separation elements intended to divert a flow of cooling liquid circulating in a direction, called axial direction, of the heat exchanger so as to direct it to a channel region in which it travels from one said end to the other in a direction, called longitudinal direction, of the orientation plates, characterized in that at least one separation element has at least one stiffening means which is integral at least with one region of said separation element. This makes it possible to reduce the vibratory amplitudes and/or to guide the fluid.
Heat exchangers generally have a rectangular shape the largest dimension of which is parallel to the direction of the non-diverted flow of the cooling fluid. The orientation plates are generally rectangular and have a length which is parallel to the direction of flow of the fluid in the channels.
The invention applies also to other geometries. That being so, in the sense of the present application, the term xe2x80x9caxialxe2x80x9d is understood as designating the direction of flow of the cooling fluid when it is not diverted by an orientation plate, and the term xe2x80x9clongitudinal direction of the orientation platesxe2x80x9d is understood as the general direction of flow of the fluid along the channel or channels, from one longitudinal end of the plates to the other.
An object of the invention is to reduce or even to eliminate the influence of these projecting regions which are not fixed to the evaporator, while further enhancing the damping obtained by the end plates by stiffening their edges and/or by limiting the transmission of the vibration in their central part.
According to the present invention there is provided a heating, ventilation and/or air-conditioning device including a thermal loop equipped with a heat exchanger, said heat exchanger consisting of a stack of orientation plates having opposite first and second longitudinal ends and defining channel regions between them in which a cooling fluid travels from one end to the other in a longitudinal direction of the orientation plates, the first and the second longitudinal ends of the orientation plates having means for directing a flow of cooling liquid either in an axial direction of the evaporator, or in a longitudinal direction of the orientation plates in a said channel region, the evaporator having end plates arranged at two opposite axial ends of the evaporator and at least a part of which, particularly of the contour, is secured, particularly by brazing, to an orientation plate, wherein at least one edge of said part has no region which is not secured to said orientation plate.
In a first variant, at least one outer edge of said part of the contour has a rim running along it which is folded over and secured to said orientation plate. In a second variant, at least one edge of said part of the contour constitutes one edge of an aperture formed in an end plate. The surface area of said aperture is advantageously equal to 20% of the total surface area of the end plate.
In one arrangement, at least some of said orientation plates are partition plates which, at least at one end, have at least one separating wall constituting a said separation element and which have at least one rib which constitutes a said stiffening means.
In a second arrangement, at least some orientation plates are plates called standard plates having, at their first and second ends, at least one boss provided with an aperture allowing axial passage of the cooling liquid and at least certain orientation plates are substantially flat and, at least at one end, have at least one separating wall the thickness of which is greater than twice the thickness of a said standard plate, this thickness advantageously being at least equal to the thickness of an end plate, and which constitutes a said stiffening means. The plate may have a substantially constant thickness, or the separating wall may even have a thickness greater than that of the rest of the plate. It is particularly advantageous for the separating wall to be profiled in such a way as to guide the cooling fluid from said axial direction of the evaporator to said longitudinal direction of the plates, which makes it possible to reduce the noise by at least partly preventing the impact due to said speed component.
In a third arrangement, the heat exchanger, for example an evaporator, consists of a stack of said standard plates and of partition plates having, at their first and second ends, at least one boss having a bearing face at least one of which has a separation element and at least one flat plate is interposed between the bearing faces of the bosses of two partition plates.
In another arrangement, the evaporator consists of a stack of said standard plates, which have a first face, particularly a flat face, and a second face, particularly a flat face, from which said bosses extend, and at least some of said flat plates are interposed between the first faces of two standard plates in such a way as to define two cooling-fluid passage half-channels, one between the first face of one of said two standard plates and a first face of said flat plate and the other between the second face of said flat plate and the first face of the other of said two standard plates.
At least one said flat plate may have at least one cooling-fluid axial passage aperture at one end.
In yet another arrangement, a said stiffening means is a stiffening plate which is interposed between a said end of two plates and which is secured to them.
The arrangements given above make it possible to deal with the problem of the noise from the partition plates, but the invention, in its first aspect, applies equally to the case of the end plates and, to this end, at least one end plate includes at least one said stiffening means.
This stiffening means may be a stiffening plate integral with one end of said end plate.
Alternatively, said stiffening means may consist of an edge of the end plate which is folded onto one face of said end plate. Alternatively again, at least one transverse edge and/or a longitudinal edge projecting from the end plate may be folded against at least one lateral surface of the heat exchanger.
In an alternative there is envisaged reducing the noise generated by the end plates by decoupling them from the mechanical stresses which they receive.
According to its second aspect, the invention relates to a heating, ventilation and/or air-conditioning device including a thermal loop equipped with a heat exchanger, for example an evaporator, said heat exchanger consisting of a stack of orientation plates having opposite first and second longitudinal ends and defining channel regions between them in which a cooling fluid travels from one said end to the other in a longitudinal direction of the orientation plates, the first and the second longitudinal ends of the orientation plates having means for directing a flow of the cooling fluid, either in an axial direction of the evaporator, or, by diverting it, in a longitudinal direction of the orientation plates in a said channel region, certain orientation plates being axial-orientation plates, and certain orientation plates being partition plates which, at least at one of their ends, divert said flow of fluid in a said channel region, the heat exchanger also having end plates arranged at two opposite axial ends of the evaporator, characterized in that at least one of the first and second longitudinal ends of at least one partition plate and/or of at least one end plate is coupled respectively to at least a first and second end of a said orientation plate (which may or may not be a partition plate) by means of a damper element. This damper element may be a stamped boss integral with the corresponding end of the end plate. This damper element may also be a corrugated metal sheet. At least one damper element is advantageously integral with a stiffening means, in such a way as to combine the damper effect and the stiffening effect, for example that obtained by a ribbed separating wall.
In a third aspect, the invention envisages reducing the noise generated by the end plates by reducing the acoustic coupling thereof with the outside of the heat exchanger, for example an evaporator. This is because the end plates are generally brazed along a contour and have free regions which project from the outside or the inside of this contour and which are not fixed to the rest of the evaporator. When the end plates are subjected to the impact due to the circulation of the cooling fluid, these projecting regions are stressed by the vibrations thus produced and are also set into vibration, which induces an acoustic coupling with the outside which is all the greater if the surface area in question is itself substantial.